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Re: Transformer core (fwd)
---------- Forwarded message ----------
Date: Fri, 8 Oct 1999 07:48:20 -0500
From: "Dr. Resonance" <Dr.Resonance-at-next-wave-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Transformer core
Scott:
Add a 0.5 Ohm, 5 kva resistor in series with the inductor and it won't
"thump" which occurs when it hits saturation of the core. The small
resistance smooths out these peaks and your coil will run smoother (whatever
that is). A lot easier on the variac for sure.
Regards,
Dr. Resonance
-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Friday, October 08, 1999 3:30 AM
Subject: Re: Transformer core
>Original Poster: Bunnykiller <bigfoo39-at-idt-dot-net>
>
>i rewound a core of similar size for ballasting my pig...
>altho i feel Dr Rez can answer this one much better than I but i will
>give you my experiences ...
>
>i ground out the welds and rewound the core with #10 solid copper
>insulated .. after rewelding the I back on I tested it on 120 V with
>a current draw of 6 amps ... but here are the details ...
>
>there are 150 turns and there is also an air gap at the center leg to
>the I bar of .060 " ( increased reluctance e.g. more current draw) the
>ends ( outside legs) are flush ( minimal gap ) to the I bar. when the
>unit is used with the pig there is a current draw of 20 - 25 amps (
>seems to surge a bit ) the unit gets warm but not enuf to damage the
>insulation on the windings. btw im using 240 on the pig input ..
>
>
>Scot D
>
>
>
>
>Tesla List wrote:
>>
>> Original Poster: "Matt Behrend" <electronxlc-at-earthlink-dot-net>
>>
>> Hi all,
>>
>> I have a large transformer core that I want to wind for my inductive
>> ballast - 13mH. It must handle 3kVA without saturating, so could
>> some of the transformer experts tell me if my core is large enough,
>> and minimum number of turns required?
>>
>> Overall dimensions are 7.5" x 6.25" x 2.5"
>> cross sectional area 1.25" x 2.5" on perimeter sides and 2.5" x
>> 2.5" in center leg of the El shape.
>>
>> This is from a 1kVA Topaz isolation transformer, but the size of the
>> core seems like it can take much more power.
>>
>> Matt Behrend
>
>